- Civil Aviation Authority (CAA)
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The Civil Aviation Authority is the UK's independent aviation regulator overseeing safety, airspace and economic regulation of civil aviation.
- Operator ID
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Unique number issued by the CAA to the person or organisation legally responsible for a drone or model aircraft. It must be affixed to any aircraft with a camera from 100 g upwards and to all drones at 250 g or more. Must be renewed every 12 months.
- Visual Line of Sight (VLOS)
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A type of flight where the remote pilot must always be able to see the drone clearly with their own eyes (not through a screen or binoculars) so they can control its direction, distance and height, and avoid other aircraft, people and obstacles. This is the basic legal requirement for Open Category flights.
- Beyond Visual Line of Sight (BVLOS)
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A type of flight where the remote pilot cannot maintain direct visual contact with the drone. BVLOS operations are only permitted under a Specific Category authorisation based on the UK SORA process, with safety measures such as detect-and-avoid systems or visual observers.
- Extended Visual Line of Sight (EVLOS)
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A disused, legacy term for flights where trained observers kept the drone in sight while the remote pilot flew beyond their own direct view. In the UK, EVLOS operations are now known as BVLOS with Visual Mitigation (BVLOS VM).
- Beyond Visual Line of Sight with Visual Mitigation (BVLOS VM)
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Previously known as EVLOS, BVLOS VM is a type of BVLOS operation that uses trained observers positioned along the flight route to watch the surrounding airspace and maintain situational awareness. BVLOS VM operations require Specific Category authorisation with clearly defined observer roles, communication methods and emergency procedures.
- Notice to Airmen / Notice to Air Missions (NOTAM)
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Short-term advisory issued by aviation authorities about temporary changes or hazards affecting flight safety. Always check relevant NOTAMs before flying, especially in the Specific or Certified Categories.
- Drone Assist / Altitude Angel Drone Safety Map
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Free interactive map from Altitude Angel, endorsed by the CAA, showing live NOTAMs, airspace restrictions and ground hazards. Helps operators plan safe flights and notify authorities in some areas.
- General Visual Line of Sight Certificate (GVC)
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A CAA-recognised remote pilot competence certificate for Specific Category operations. Under the January 2026 AMC/GM appendices to UK Regulation (EU) 2019/947, GVC remains acceptable where the Operational Authorisation permits it, and issuance is planned to discontinue on 31 December 2027 as the RPC pathway becomes the forward training route.
- A2 Certificate of Competency (A2 CofC)
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A formal qualification issued by a CAA-recognised assessment entity that permits Open Category flights in subcategory A2 (Near People). It involves an online theory exam and self-declared practical training covering meteorology, UAS mitigations and flight planning. The certificate lasts five years and must be held alongside a valid Flyer ID for A2 operations.
- Assemblies of People
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Large gatherings where people cannot move away quickly in the event of an incident, such as concerts or sporting events. Drone flights over or near assemblies are heavily restricted or prohibited.
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Remote Pilot Certificate (RPC-L1, RPC-L2, RPC-L3)
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A tiered qualification issued by a CAA-approved RAE(PC). The certificate confirms that the remote pilot has demonstrated the requisite knowledge, skills and operational judgement to conduct drone operations of increasing complexity and risk, from basic Visual Line-of-Sight (VLOS) tasks to advanced Beyond Visual Line of Sight (BVLOS) missions in more challenging airspaces.
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RPC-L1: Entry-level qualification for VLOS operations within a UK SORA-based authorisation (or equivalent) for aeroplane/fixed-wing or rotorcraft/multirotor, valid for five years and now recognised as an alternative to the GVC for PDRA-01.
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RPC-L2: Intermediate level enabling VLOS and limited BVLOS in segregated airspace (ARC-a), requiring minimum logged hours and L1 holding, valid for three years.
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RPC-L3: Advanced level covering BVLOS in moderate-risk airspace (ARC-b/c), additional prerequisites apply (e.g. logged BVLOS hours, medical certificate), valid for three years.
The certification pathway ensures that the pilot's competence aligns with the assessed operational risk level, the higher the risk (air risk, ground risk, airspace complexity), the higher the required RPC level.
- Drone and Model Aircraft Code
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Official UK rules and guidance for flying drones and model aircraft safely and legally in the Open Category, covering privacy, safety and airspace awareness. Every pilot should follow the Code.
- Specific Operations Risk Assessment (UK SORA)
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The CAA's structured approval process for Specific Category missions outside predefined scenarios. UK SORA steps through establishing the Ground Risk Class, Air Risk Class and Specific Assurance and Integrity Level, then allocates Operational Safety Objectives and mitigations. It replaced the Operating Safety Case approach on 23 April 2025.
- Ground Risk Class (GRC)
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A UK SORA rating that measures the potential harm an operation could cause to people or critical infrastructure on the ground. It considers the aircraft's kinetic energy, population density and containment measures to produce a class that feeds into the overall SAIL determination.
- Air Risk Class (ARC)
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The UK SORA measure of collision risk with other airspace users. Values range from ARC-a (very low traffic) through ARC-d (high-density traffic) and may be lowered with strategic mitigations such as airspace coordination. The resulting ARC helps determine which air risk mitigations and OSOs are mandatory.
- Specific Assurance and Integrity Level (SAIL)
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The assurance level assigned in Step 5 of UK SORA by combining the final Ground Risk Class and Air Risk Class. SAIL levels I to VI dictate how rigorous the Operational Safety Objectives, technical assurance and organisational processes must be before the CAA issues an authorisation.
- Recognised Assessment Entity for Pilot Competence (RAE(PC))
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A legal entity approved by the CAA to train, examine and certificate remote pilots under UK Regulation (EU) 2019/947. CAP 722B details the personnel, facilities, procedures, insurance and quality system an organisation must maintain to become and stay approved as an RAE(PC).
Once approved, an RAE(PC) can deliver ground school, supervise practical flight training, conduct assessments and issue Remote Pilot Certificates used to demonstrate remote pilot competence.
- Recognised Assessment Entity for Flightworthiness (RAE(F))
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A CAA-approved organisation that evaluates whether an unmanned aircraft system or configuration meets the technical requirements needed for Specific Category authorisations. CAP 722J explains how an RAE(F) assesses design, construction, maintenance and containment evidence, then issues a flightworthiness statement supporting the applicant's UK SORA submission.
RAE(F) involvement is typically mandated for higher-risk operations (SAIL III and above) where independent engineering assurance and integrity evidence are required before the CAA will grant approval.
- Pre-Defined Risk Assessment 01 (PDRA-01)
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Standard risk assessment published by the CAA allowing approved VLOS operations in built-up areas under the Specific Category. Operators comply with fixed limits and mitigations to fly without submitting a full SORA.
- Flyer ID
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Identification number issued by the CAA to a remote pilot who passes the online theory test; required before flying any drone or model aircraft that weighs 100 g or more. Valid for five years and strongly recommended for lighter aircraft.
- Model Aircraft
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An unmanned aircraft used for sporting and recreational purposes, flown by direct control inputs made by the remote pilot without any autonomous capability other than for flight stabilisation purposes.
Note: The definition of a model aircraft may include multi-rotor type drones. Any unmanned aircraft being flown in accordance with the definition above is considered a model aircraft. The use of any automation, such as automatic flight modes that alter the aircraft’s position, places the operation outside the definition of a model aircraft and therefore outside the scope of Article 16. The aircraft must be flown with direct control inputs from the remote pilot.
It is acknowledged that many unmanned aircraft have built-in failsafe modes that may activate in certain situations, such as loss of control link. Activation of such a mode, although automatic, does not necessarily place the aircraft outside the scope of the model aircraft definition.
- Operational Authorisation (OA)
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Written permission from the CAA allowing drone flights in the Specific Category, such as PDRA-01 or UK SORA operations. It sets the limits and safety requirements beyond the Open Category rules.
- Specific Category
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The medium-risk category defined in UK Regulation (EU) 2019/947 for drone operations that exceed Open Category limits but do not require full aviation certification. Every Specific Category flight needs either a CAA predefined risk assessment approval (such as PDRA-01) or a bespoke UK SORA-based Operational Authorisation.
- Certified Category
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The highest-risk category in UK Regulation (EU) 2019/947 for unmanned aircraft missions that match the risk profile of traditional aviation. Operations typically involve passenger transport, dangerous goods or overflight of assemblies of people and require aircraft certification, approved operators, and licensed remote pilots, mirroring manned aviation requirements.
- Unmanned Aircraft System (UAS)
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An unmanned aircraft together with the control station and data-link equipment needed for safe operation; commonly called a drone.
- General Data Protection Regulation (GDPR)
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The UK's version of the EU GDPR governing the processing of personal data. Drone operators must comply when capturing personal data.
- Information Commissioner's Office (ICO)
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The UK's independent authority that promotes openness by public bodies and safeguards individual data privacy rights.
- Aeronautical Information Publication (AIP)
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Official publication containing aeronautical information essential to air navigation, including UK airspace data.
- National Air Traffic Services (NATS)
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The UK's main air traffic control service provider managing civil airspace.
- Civil Aviation Publication 722 (CAP 722)
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CAA guidance series providing policy and best practice for unmanned aircraft system operations.
- Operations Manual
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A controlled document that describes how a UAS operator manages safety, compliance and mission execution. UK Reg (EU) 2019/947 requires Specific Category applicants to maintain a current Operations Manual covering organisational structure, risk assessments, normal and emergency procedures, and aircraft maintenance arrangements.
- Operating Safety Case (OSC)
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The former CAA approval route for complex drone missions prior to 23 April 2025. Operators submitted a multi-volume safety case demonstrating mitigations for their concept of operations. The process has now been superseded by the UK SORA methodology for new Specific Category applications.
- Flight Restriction Zone (FRZ)
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Legally defined zone around a protected aerodrome comprising its ATZ and runway protection areas; drones may enter only with explicit aerodrome or ATC permission.
- Aerodrome Traffic Zone (ATZ)
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Cylinder of airspace, typically 2 NM radius up to 2 000 ft AAL, established to protect traffic at an aerodrome and forming part of many FRZs.
- Runway Protection Zone (RPZ)
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Rectangular airspace about 5 km long and 1 km wide extending from each runway threshold up to 2 000 ft AAL; combined with the ATZ to create the FRZ.
- Radio Mandatory Zone (RMZ)
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Airspace in which two-way radio contact with the relevant ATS unit is mandatory before entry and throughout the flight.
- Small Unmanned Aircraft , General (ANO Article 94)
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Core rules for small unmanned aircraft under 20 kg requiring safe flight, visual contact and respect for people and property. Many obligations now appear in the Drone and Model Aircraft Code.
- Small Unmanned Aircraft , Prohibitions (ANO Article 94A)
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Prohibits flying a small unmanned aircraft in certain circumstances, such as inside an FRZ without permission or contrary to airspace restrictions. Breach of Article 94A is a criminal offence.
- Small Unmanned Aircraft , Commercial Operations (ANO Article 94B)
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Former provision regulating commercial drone operations, now largely replaced by UK UAS regulations and Operational Authorisations. Retained in amended form for certain legacy scenarios and enforcement.
- Small Unmanned Surveillance Aircraft (ANO Article 95)
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Adds extra restrictions to drones fitted with cameras or sensors, including separation from congested areas and people. Certain allowances exist in the Open Category.
- Endangering Safety of an Aircraft (ANO Article 240)
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Makes it illegal to recklessly or negligently cause or permit an aircraft, including a drone, to endanger another aircraft. Applies regardless of the unmanned aircraft's weight and carries severe penalties.
- Endangering Safety of Any Person or Property (ANO Article 241)
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Makes it an offence to recklessly or negligently endanger any person or property with an aircraft. This provision can be enforced even when other drone rules are not breached.
- UAS Operations in the Framework of Model Aircraft Clubs and Associations (Article 16 of UK Reg (EU) 2019/947)
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Allows the CAA to authorise recognised clubs and associations to fly under their own conditions. Members must follow the specific limits, sites and procedures set out in their association's Article 16 authorisation.
- Power to Issue Directions (ANO Article 265)
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Gives the CAA or authorised persons the ability to issue immediate directions restricting or prohibiting flight for safety or security reasons. These may be published as NOTAMs or formal notices.
- UK Reg (EU) 785/2004
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Retained UK regulation originating from EU 785/2004 that sets minimum insurance requirements for commercial air carriers and operators, including drones.
- Transponder Mandatory Zone (TMZ)
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Airspace where all aircraft must carry and operate an SSR Mode S transponder unless exempted.
- Open Category
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One of three UAS operation categories in UK Regulation (EU) 2019/947, covering low-risk flights in subcategories A1, A2 and A3. No CAA Operational Authorisation is required if all limits, such as weight under 25 kg, height ≤ 120 m and separation from people, are met.
- First Person View (FPV)
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Flying a drone using a live video feed from an onboard camera viewed through goggles or a screen. In the Open Category this is only allowed when a competent observer maintains unaided visual line of sight and can warn the pilot of hazards.
- Flight Level 660 (FL660)
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Altitude of 66,000 ft referenced to the standard pressure setting of 1013.25 hPa. Represents the upper limit of UK-controlled airspace used in the UK SORA policy framework.
- Competent Observer
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A person who maintains direct, unaided visual line of sight (VLOS) of the unmanned aircraft at all times during First Person View (FPV) flying, or during BVLOS with visual mitigation, where the pilot is unable to maintain VLOS themselves. The observer must be able to communicate clearly with the pilot and monitor the surrounding airspace to warn of hazards, other aircraft, people, or obstacles. The observer does not require a Flyer ID or formal qualification, but must be briefed by the pilot and able to perform this role effectively.
- Remote Identification (Remote ID)
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A technology that allows a drone to broadcast or transmit its identity, location and operator information during flight. Remote ID enables authorities and other airspace users to identify drones in real time, supporting accountability and airspace safety. From 2026, certain drones in the UK will be required to broadcast Remote ID based on their class mark and operation category.
- Dangerous Goods
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Articles or substances that pose a risk to health, safety, property or the environment when carried by air, as classified in the ICAO Technical Instructions adopted by the CAA. Transporting dangerous goods by drone normally requires Specific or Certified Category approval with explicit procedures, packaging standards and emergency plans agreed with the regulator.
- Air Accidents Investigation Branch (AAIB)
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UK government body that investigates civil aircraft accidents and serious incidents, including those involving drones. Serious occurrences must be reported to the AAIB without delay.
- Class Mark
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A label assigned to a drone by the manufacturer to show it meets specific UK or EU regulatory standards. Each class mark (such as UK0 to UK6 in the UK system) defines technical and safety features like weight limits, Remote ID capability and built-in safety measures. The class mark determines which Open Category subcategory a drone can be flown in and the pilot qualifications required.
